kbuci commented on code in PR #10965:
URL: https://github.com/apache/hudi/pull/10965#discussion_r1556395911
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hudi-client/hudi-client-common/src/main/java/org/apache/hudi/client/BaseHoodieWriteClient.java:
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@@ -1135,8 +1138,34 @@ protected void
completeLogCompaction(HoodieCommitMetadata metadata, HoodieTable
*/
protected HoodieWriteMetadata<O> compact(String compactionInstantTime,
boolean shouldComplete) {
HoodieTable table = createTable(config, context.getHadoopConf().get());
+ Option<HoodieInstant> instantToCompactOption =
Option.fromJavaOptional(table.getActiveTimeline()
+ .filterCompletedAndCompactionInstants()
+ .getInstants()
+ .stream()
+ .filter(instant ->
HoodieActiveTimeline.EQUALS.test(instant.getTimestamp(), compactionInstantTime))
+ .findFirst());
+ try {
+ // Transaction serves to ensure only one compact job for this instant
will start heartbeat, and any other concurrent
+ // compact job will abort if they attempt to execute compact before
heartbeat expires
+ // Note that as long as all jobs for this table use this API for
compact, then this alone should prevent
+ // compact rollbacks from running concurrently to compact commits.
+ txnManager.beginTransaction(instantToCompactOption,
txnManager.getLastCompletedTransactionOwner());
+ try {
+ if (!this.heartbeatClient.isHeartbeatExpired(compactionInstantTime)) {
+ throw new HoodieLockException("Cannot compact instant " +
compactionInstantTime + " due to heartbeat by existing job");
+ }
+ } catch (IOException e) {
+ throw new HoodieHeartbeatException("Error accessing heartbeat of
instant to compact " + compactionInstantTime, e);
+ }
+ this.heartbeatClient.start(compactionInstantTime);
+ } finally {
+ txnManager.endTransaction(txnManager.getCurrentTransactionOwner());
+ }
preWrite(compactionInstantTime, WriteOperationType.COMPACT,
table.getMetaClient());
- return tableServiceClient.compact(compactionInstantTime, shouldComplete);
+ HoodieWriteMetadata compactMetadata =
tableServiceClient.compact(compactionInstantTime, shouldComplete);
+ this.heartbeatClient.stop(compactionInstantTime, true);
Review Comment:
I was looking into a UT failure in
`org.apache.hudi.table.functional.TestHoodieSparkMergeOnReadTableInsertUpdateDelete#testRepeatedRollbackOfCompaction`
where two compact executions of the same instant time are called back to back
(my understanding is that this is supposed to verify that the second compact
does a no-op and succeeds upon seeing that plan is already committed).
I realized that with this change, the second compact call was failing due to
calling `isHeartbeatExpired` and seeing an active heartbeat (from the first
attempt) still running, despite the fact that here we are stopping the
heartbeat after a successfully completing the compact. The reason that
`isHeartbeatExpired` was unexpectedly `false` here is that
1. `isHeartbeatExpired` will return false if instant time is too recent,
even if the heartbeat has been stopped (in the in-memory mapping)
2. When
`org.apache.hudi.client.heartbeat.HoodieHeartbeatClient#stop(java.lang.String)`
is called (by the first compact call in UT) the heartbeat file is deleted and
the heartbeat in in-memory mapping is stopped (as expected). But this means
that the heartbeat cannot be started again (even if (1) is resolved), since
heartbeat API doesn't allow caller to start a heartbeat that is present in
in-memory mapping and has heartbeatStopped flag set to true.
In order to get around this issue, I added another API in heartbeat API
similar to stop, except that it removes the desired heartbeat from the
in-memory mapping (forcing any future compact call in the same job to re-read
the heartbeat files from DFS and create a new heartbeat in the in-memory
mapping ). Though not sure if there might be a better approach here. I assume
this existing functionality isn't a bug, as it makes sense for commits that
cannot be repeatedly re-executed (like ingestion COMMITs), and I assume the
issue here stems from the fact that for compact we need to potentially
repeatedly restart stopped heartbeats
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